Bacteria related information from the Penn State referece provided by "Dantheman".

Do the pond bacteria being sold today really help breakdown the muck layer?
Use of bacteria to breakdown muck layers is overblown. It will help a little bit, but it is slow. The benefit would depend on how much of the muck is organic (leaves, etc.) versus sediment. Bacteria can act to reduce organic muck, but they can’t breakdown mineral sediment particles. Overall, you should not expect more than a few inches of reduction in muck from bacteria products. It is not reasonable to look at these products as a way to avoid dredging.

Do the enzyme products sold on the market really work at removing nutrients and devouring bottom sludge?
There are two different issues with the enzymes. Some are marketed for sludge reduction while others are for nutrient control. Our early experience with bacteria/enzyme products is promising for nutrient control and reduced algae and plant growth, but there are some considerations when using these products. They can be very expensive and must be applied at least once per year because of our cold climate.

Source: Penn State Cooperative Extension Pond Management Website and PA Fish and Boat Commission Pond Website
Prepared by Jim Clark, Extension Educator in McKean County.

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